The nutritional management of depression has long been discussed, due to the perceived benefit of a nutritional product having less side effects than pharmaceutical agents. Candidate nutrients for managing depression include vitamin D, B vitamins, tryptophan, branch chain amino acids, probiotics, omega-3 fatty acids, folate/methylfolate (also known as vitamin B9), and s-adenosylmethionine. This paper provides a narrative review of three nutrients which have significant scientific support for the management of depression. A deficiency in each nutrient is associated with depression, and interventional studies indicate that the correction of the nutritional deficiency may provide clinical benefit. We present epidemiological evidence, a mechanistic explanation and a review of interventional studies for these nutrients. Finally, relevant nutritional guidelines are presented with their conclusion for the role of each nutrient in the management of depression.

BACKGROUND: Holocarboxylase synthetase deficiency (HLCS deficiency, OMIM #253270) is an exceedingly rare metabolic disorder resulting in multiple carboxylase deficiencies owing to impaired biotin cycle. Clinical manifestations include severe metabolic acidosis, hyperammonemia, tachypnea, skin rash, alopecia, feeding problems, hypotonia, developmental delay, seizures, and, in severe cases, death.
RESULTS: An 8-day-old female neonate presented with severe lactic acidosis, necessitating sedation and mechanical ventilation. Despite receiving supportive care, no evident clinical improvement was observed, accompanied by the onset of generalized ichthyosis. Genetic analysis of actionable metabolic disorders revealed compound heterozygous variants of HLCS (NM_000411.8), specifically c.[710T>C (p.Leu237Pro)]; [1544G>A (p.Ser515Asn)], prompting the initiation of biotin mega-dose therapy (10 mg/day). Remarkably, dramatic clinical improvement in lactic acidosis was observed the day after initiating biotin administration, leading to the discontinuation of mechanical ventilation within 6 days. The patient remained in stable condition during follow-up, exhibiting normal growth and development along with consistently stable laboratory findings up to 18 months of age.
CONCLUSIONS: Our case highlights the significance of early genetic testing in neonates with unexplained metabolic disorders to enable timely diagnosis and therapy initiation. Biotin therapy has demonstrated remarkable efficacy in improving the clinical condition of patients with HLCS deficiency, leading to favorable outcomes.

A compromised capacity to maintain NAD pools is recognized as a key underlying pathophysiological feature of neurodegenerative diseases. NAD acts as a substrate in major cell functions including mitochondrial homeostasis, cell signalling, axonal transport, axon/Wallerian degeneration, and neuronal energy supply. Dendritic degeneration is an early marker of neuronal stress and precedes cell loss. However, little is known about dendritic structural preservation in pathologic environments and remodelling in mature neurons. Retinal ganglion cell dendritic atrophy is an early pathological feature in animal models of the disease and has been demonstrated in port-mortem human glaucoma samples. Here we report that a nicotinamide (a precursor to NAD through the NAD salvage pathway) enriched diet provides robust retinal ganglion cell dendritic protection and preserves dendritic structure in a rat model of experimental glaucoma. Metabolomic analysis of optic nerve samples from the same animals demonstrates that nicotinamide provides robust metabolic neuroprotection in glaucoma. Advances in our understanding of retinal ganglion cell metabolic profiles shed light on the energetic shift that triggers early neuronal changes in neurodegenerative diseases. As nicotinamide can improve visual function short term in existing glaucoma patients, we hypothesize that a portion of this visual recovery may be due to dendritic preservation in stressed, but not yet fully degenerated, retinal ganglion cells.

Carcinogenesis is closely related to the expression, maintenance, and stability of DNA. These processes are regulated by one-carbon metabolism (1CM), which involves several vitamins of the complex B (folate, B2, B6, and B12), whereas alcohol disrupts the cycle due to the inhibition of folate activity. The relationship between nutrients related to 1CM (all aforementioned vitamins and alcohol) in breast cancer has been reviewed. The interplay of genes related to 1CM was also analyzed. Single nucleotide polymorphisms located in those genes were selected by considering the minor allele frequency in the Caucasian population and the linkage disequilibrium. These genes were used to perform several in silico functional analyses (considering corrected p-values < 0.05 as statistically significant) using various tools (FUMA, ShinyGO, and REVIGO) and databases such as the Kyoto Encyclopedia of Genes and Genomes (KEGG) and GeneOntology (GO). The results of this study showed that intake of 1CM-related B-complex vitamins is key to preventing breast cancer development and survival. Also, the genes involved in 1CM are overexpressed in mammary breast tissue and participate in a wide variety of biological phenomena related to cancer. Moreover, these genes are involved in alterations that give rise to several types of neoplasms, including breast cancer. Thus, this study supports the role of one-carbon metabolism B-complex vitamins and genes in breast cancer; the interaction between both should be addressed in future studies.

BACKGROUND: It is proven that B vitamins through promote a wide range of metabolic pathways in animals as cofactors improve animal performance.
OBJECTIVE: This study was conducted to investigate the impacts of maternal B complex vitamin injection on performance and plasma parameters in goats and their offspring, as well as the faeces status of newborn kids.
METHODS: In this research, the pregnant goats (3 years old) were randomly divided into two groups: the control group (without B complex vitamin injection) and the B complex vitamin group (5 mL B complex vitamin injection per animal). The animals were injected with 5 mL B complex vitamin twice during the transition period (5 weeks pre- and 5 weeks post-kidding). The goats during the transition period and kids on days 10, 20 and 30 were weighed. Feed intake by goats and consumption of milk and starter in kids were recorded daily. The dry matter digestibility by kids was tested by collecting samples of faeces and feed for 5 days in the last week. Chemical analysis was determined using the AOAC method. The kids\' faeces were prepared daily during the study. The blood samples of goats and newborn kids were taken 7 days after kidding. Then, levels of B group vitamin, as well as concentrations of liver enzymes, thyroid hormones and immunological parameters, were determined in plasma of goat and their offspring. In addition, concentrations of glucose and insulin were measured in goat plasma (Asadi et al., 2024).
RESULTS: According to results, the performances of goats and their offspring, as well as kids\' faeces status, were improved by maternal B complex vitamin injection (p < 0.0001). The levels of cobalamin, pyridoxine, thiamine, folic acid, nicotinic, pantothenic and unconjugated pteridine increased in the plasma of goats and their kids in the B complex vitamin group compared with the control group during the transition period (p < 0.0001). Injection of maternal B complex vitamin raised the plasma levels of triiodothyronine and tetraiodothyronine, immunoglobulin G and immunoglobulin M in goats and their offspring (p < 0.0001). Higher levels of glucose and lower levels of insulin were determined in the goats injected with B complex vitamin (p < 0.0001).
CONCLUSIONS: These results suggest that maternal B complex vitamin injection is required for the improvement of performance, health status and the blood plasma parameters in pregnant goats and their kids.

The policies regarding the mandatory fortification of food with folic acid (FA) may impact the effectiveness of folate-based B vitamin treatment on cognitive function in older adults. We critically and systematically review the literature to assess whether food fortification policies affect folate-based B vitamin treatment efficacy on cognition function in older adults. Electronic databases, including PubMed, Web of Science, and CNKI, were searched for \"Cognitive Function\", \"Folate\", and \"Older Adults\". The study had specific criteria for inclusion, which were as follows: (1) the studies should initially have randomized controlled trials that were conducted on older adults aged 60 or above; (2) the studies must assess the relationship between folate status and cognitive performance; and (3) the studies should clarify the policies regarding food fortification with FA. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Two reviewers independently extracted all the data, and any discrepancies were resolved by consensus. All the data collected were compiled, compared, and analyzed critically. Random effects models were used to assess the effects of interventions. The systematic review included fifty-one articles involving 42,768 participants. Of these, the 23 articles were included in the meta-analysis. The meta-analysis on the effects of folate-based B vitamin supplementation on cognitive function showed a significant overall impact (Z = 3.84; p = 0.0001; SMD, 0.18; 95% CI, 0.09, 0.28). Further analysis revealed that FA food fortification policies were not implemented in countries where folate-based B vitamin supplementation improved cognitive impairment in older adults (Z = 3.75; p = 0.0002; SMD, 0.27; 95% CI, 0.13, 0.40). However, the FA intervention did not have significant outcomes in areas where FA food fortification policies were mandatory (Z = 0.75; p = 0.45; SMD, 0.03; 95% CI, -0.06, 0.13). Supplementing with oral folic acid, alone or in combination, has been linked to improved cognitive performance in older adults. While mandatory FA fortification has the improved folic acid status, additional folate-based B vitamin supplements do not appear to influence cognitive function.

Previous studies show that B vitamins and homocysteine (Hcy) may be associated with mental disorders, but the accurate causal relationship remains unclear. This study aimed to elucidate the potential causal relationship of serum B vitamins and Hcy levels with five common mental disorders through a two-sample Mendelian randomization (MR) study. In this MR analysis, 50 single-nucleotide polymorphisms (SNPs)-13 related to folate, 17 to vitamin B6, 8 to vitamin B12 and 12 to Hcy-were obtained from a large-scale Genome-Wide Association Studies (GWAS) database and employed as instrumental variables (IVs). The MR analyses were conducted using the inverse variance weighted (IVW), weighted median (WM), MR-Egger methods and sensitivity analyses were further performed to test the robustness. This MR study found a suggestive causal relationships between serum vitamin B12 levels and the risk of anxiety disorders (odds ratio (OR): 1.34, 95% confidence interval (CI): 1.01-1.78, p = 0.046) and bipolar affective disorders (OR: 1.85, 95% CI: 1.16-2.96, p = 0.010). However, folate, vitamin B6 and Hcy levels may not be causally associated with the risk of mental disorders. In conclusion, this study reveals that elevated serum vitamin B12 levels might suggestively increase the risk of anxiety and bipolar affective disorders, even though horizontal pleiotropy cannot be completely eliminated. The potential implications of our results warrant validation in larger GWAS based on diverse populations.

Ticks, like other obligatory blood-feeding arthropods, rely on endosymbiotic bacteria to supplement their diet with B vitamins lacking in blood. It has been suggested that additional metabolites such as L-proline may be involved in this nutritional symbiosis, but this has yet to be tested. Here, we studied the metabolite-based interaction between the brown dog tick Rhipicephalus sanguineus (Acari: Ixodidae) and its Coxiella-like endosymbionts (CLE). We measured amino acid titers and tested the effect of B vitamins and L-proline supplementation on the fitness of CLE-suppressed female ticks, displaying low titers of CLE. We found higher titers of L-proline in the symbiont-hosting organs of unfed ticks and in engorged blood-fed whole ticks. Supplementation of B vitamins increased the hatching rate of CLE-suppressed ticks; this effect appears to be stronger when L-proline is added. Our results indicate that L-proline is produced by CLE, and we suggest that CLE is essential in states of high metabolic demand that affects tick reproductive fitness, such as oogenesis and embryonic development. These findings demonstrate the broader effect of nutritional symbionts on their hosts and may potentially contribute to the control of ticks and tick-borne diseases.
OBJECTIVE: Coxiella-like endosymbionts (CLE) are essential to the brown dog tick Rhipicephalus sanguineus for feeding and reproduction. This symbiosis is based on the supplementation of B vitamins lacking in the blood diet. The involvement of additional metabolites has been suggested, but no experimental evidence is available as yet to confirm a metabolic interaction. Here, we show that B vitamins and L-proline, both of which contribute to tick reproductive fitness, are produced by CLE. These findings demonstrate the importance of symbiont-derived metabolites for the host\'s persistence and shed light on the complex bacteria-host metabolic interaction, which can be channeled to manipulate and control tick populations.

BACKGROUND: Chronic heart failure (CHF) has always posed a significant threat to human survival and health. The efficacy of thiamine supplementation in CHF patients remains uncertain.
OBJECTIVE: Receiving supplementary thiamine may not confer benefits to patients with CHF.
METHODS: A comprehensive search was conducted across the Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov, and Web of Science databases up until May 2023 to identify articles investigating the effects of thiamine supplementation in CHF patients. Predefined criteria were utilized for selecting data on study characteristics and results.
RESULTS: Seven randomized, double-blind, controlled trials (five parallel trials and two crossover trials) involving a total of 274 patients were enrolled. The results of the meta-analysis pooling these studies did not reveal any significant effect of thiamine treatment compared with placebo on left ventricular ejection fraction (WMD = 1.653%, 95% CI:  -1.098 to 4.405, p = 0.239, I2 = 61.8%), left ventricular end-diastolic volume (WMD = -6.831 mL, 95% CI:  -26.367 to 12.704, p = 0.493, I2 = 0.0%), 6-min walking test (WMD = 16.526 m, 95% CI:  -36.582 to 69.634, p = 0.542, I2 = 66.3%), N-terminal pro-B type natriuretic peptide (WMD = 258.150 pg/mL, 95% CI:  -236.406 to 752.707, p = 0.306, I2 = 21.6%), or New York Heart Association class (WMD = -0.223, 95% CI:  -0.781 to 0.335, p = 0.434, I2 = 87.1%). However, it effectively improved the status of thiamine deficiency (TD).
CONCLUSIONS: Our meta-analysis indicates that thiamine supplementation does not have a direct therapeutic effect on CHF, except for correcting TD.

Depression is a major global health concern expected to worsen by 2030. In 2019, 28 million individuals were affected by depressive disorders. Dietary and supplemental vitamins show overall favorable preventative and therapeutic effects on depression. B vitamins are crucial for neurological function and mood regulation. Deficiencies in these vitamins are linked to depression. Studies on individual B vitamins show promise in improving depressive symptoms, particularly thiamin, riboflavin, niacin, and folate. Vitamin C deficiency may heighten depressive symptoms, but its exact role is not fully understood. Seasonal Affective Disorder (SAD) is associated with insufficient sunlight exposure and vitamin D deficiency. Vitamin D supplementation for SAD shows inconsistent results due to methodological variations. Further investigation is needed to understand the mechanisms of vitamins in depression treatment. Moreover, more research on SAD and light therapy\'s efficacy and underlying mechanisms involving photoreceptors, enzymes, and immune markers is needed. Although dietary and supplemental vitamins show overall favorable preventative and therapeutic effects on depression, dietitians treating psychiatric disorders face challenges due to diverse study designs, making direct comparisons difficult. Therefore, this article reviews the current literature to assess the role of dietary and supplemental vitamins in the prevention and treatment of depression. This review found that, although evidence supports the role of B vitamins and vitamins C and D in preventing and treating depression, further research is needed to clarify their mechanisms of action and determine the most effective intervention strategies.